It requires 350 joules to raise a certain amount of a substance from [tex]$10.0^{\circ} C$[/tex] to [tex]$30.0^{\circ} C$[/tex]. The specific heat of the substance is [tex]$1.2 J / g ^{\circ} C$[/tex].

What is the mass of the substance?

A. 12 g
B. 15 g
C. 18 g
D. 30 g



Answer :

To solve for the mass of the substance, we use the formula for heat transfer:

[tex]\[ Q = mcΔT \][/tex]

where:
- [tex]\( Q \)[/tex] is the amount of heat added (in joules),
- [tex]\( m \)[/tex] is the mass of the substance (in grams),
- [tex]\( c \)[/tex] is the specific heat capacity (in joules per gram per degree Celsius),
- [tex]\( ΔT \)[/tex] is the change in temperature (in degrees Celsius).

Given:
- [tex]\( Q = 350 \)[/tex] joules,
- [tex]\( c = 1.2 \)[/tex] joules per gram per degree Celsius,
- The initial temperature [tex]\( T_i = 10.0^{\circ} C \)[/tex],
- The final temperature [tex]\( T_f = 30.0^{\circ} C \)[/tex].

First, calculate the change in temperature [tex]\( ΔT \)[/tex]:

[tex]\[ ΔT = T_f - T_i = 30.0 - 10.0 = 20.0^{\circ} C \][/tex]

Next, rearrange the formula to solve for the mass [tex]\( m \)[/tex]:

[tex]\[ m = \frac{Q}{cΔT} \][/tex]

Substitute the given values into the formula:

[tex]\[ m = \frac{350 \, \text{joules}}{1.2 \, \text{J/g} \cdot 20.0^{\circ} C} \][/tex]

[tex]\[ m = \frac{350}{1.2 \times 20.0} \][/tex]

[tex]\[ m = \frac{350}{24} \][/tex]

[tex]\[ m ≈ 14.583333333333334 \, \text{grams} \][/tex]

Therefore, the mass of the substance is approximately [tex]\( 14.58 \)[/tex] grams. The closest answer is:

15 grams.